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How Long Does It Take for a Reverse Osmosis System to Make Fresh Water From Saltwater

While water is one of the essential requirements for human life, more than 97% of the world’s water is salt water, making it unsuitable for drinking, irrigation, or most other uses.


If you’re considering investing in a reverse osmosis system to produce fresh water for your business, you may wonder how long the process takes. Keeping track of how long it takes to produce clean water can aid process optimization and planning.


The average time a reverse osmosis (RO) system takes to make fresh water from saltwater can vary depending on the feed water quality, the number of dissolved solids in the feed water, and the operating pressure level. Generally, most RO systems can desalinate between 24-36 gallons per hour. 


This blog post will tell you everything you need to know about the average time it takes for a reverse osmosis system to do its job.


Let’s start with the basics and examine the primary purpose of reverse osmosis systems and how they might help cruisers.


how to make fresh water from salt water 

What Is Desalination and How Does It Work?

Reverse osmosis is a process that is used to remove dissolved minerals and impurities from water by using pressure to force water molecules through a semipermeable membrane. This process is often used in desalination plants to remove salt and other impurities from seawater to turn it into fresh drinking water.


For the reverse osmosis system to work, the saltwater must be pressurized through the tiny pores of the semipermeable membrane. The membrane’s pores are small enough to allow water molecules through, but they are too small for salt molecules or other impurities to pass through.


As the saltwater is forced through the membrane’s pores, the impurities are left behind, and the only thing that comes out on the other side is fresh water. 


Four main components usually form these systems:


  1. A pre-filter: The pre-filter helps to remove any large particles or sediment from the water before it enters the RO system.

  2. Semi-permeable membrane: The semipermeable membrane is where the magic happens and where all dissolved minerals and impurities are removed from the water.

  3. Post-filter: The post-filter helps to remove any remaining particulates or impurities that might have made it past the semi-permeable membrane.

  4. Storage tank: Finally, the storage tank holds all the freshly made freshwater until you are ready to use it.


The process is relatively simple and efficient, making it a popular choice for businesses that need to produce large quantities of fresh water regularly. But how long does the process take? And that brings us to the next point in this article. 

The Time to Make Fresh Water From Saltwater Depends on Each Water Maker

The time it takes to purify salt water to drink depends on the water maker. Some water makers can create fresh water in a few hours, while others may take more time.


The size, capacity, and other features added to the water maker also play a role in production time.

How Do You Measure the Production Time?

drinkable water production 

Production Capacity

Understanding the units of measurement for freshwater output might help you choose a water maker more quickly.


Watermakers’ capacity is usually measured in Gallons Per Hour (GPH) or Gallons Per Day (GPD0 since they aim to produce large amounts of water.


Gallon Per Hour and Gallon Per Day are units in the volume flow rate category widely used in the American unit system. This quantifies the volume that goes across an area per unit of time.


In the case of RO systems, you can easily identify how long it takes to make fresh water from salt water by observing the specifics. 


Feed Water Quality 

Feed water quality is important in determining how long it will take to make fresh water. If the feed water is high in dissolved solids, it will take longer for the RO system to work. The operating pressure level also plays a role; higher pressures will increase production but put additional strain on the system.   

Production Rates 

RO systems typically produce 24 and 36 gallons of fresh water per hour. This includes drinking water and water used for cooking, cleaning, and other purposes. Larger systems may produce more water, while smaller units may make less. 


drinkable water production

Let’s see an example.


A company dedicated to cruising has been having trouble making drinkable water. One of the improvement opportunities they noticed was the time of water production. So, one of their main objectives is to find a suitable system that doesn’t take more than one hour to produce at least 50 gallons of water.


Our Honda EU2000i desalination system can be the best chance to improve their water production time. This system to power 20 or 60 GPD or 480 to 1440 GPD, depending on the model. 


Generally speaking, the larger the water maker, the faster it can produce fresh water. Additionally, water makers with higher capacities will typically be able to make fresh water more quickly than those with lower powers.

Get the Best Quality RO Systems for Boats and Yachts

In conclusion, reverse osmosis systems are an efficient way to turn saltwater into freshwater while saving time.


If you’re considering investing in a reverse osmosis system for your business, contact us, and we will gladly asses you on finding the most time-effective watermaker for your specific needs.

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